Doubly Linked list in python

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Doubly Linked list

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The doubly linked list is similar to a single linked list, add a new pointer to this concept,The list attached to Doubly can be seen in both the front and back directions, as in the image,And the double link is using more space in the program, we will teach you how to make double link in python, doubly linked list have to use next point and previous,
In this image the prev is store the previous node value and The process is running continuously, so you check the code how to create a list with double links,

Code

	class node:
	def __init__(self,data=None):
	self.data=data;
	self.next=None;
	self.prev=None;
	class DoublyLinked ():
	def __init__(self):
	self.head=None;
	def adddata(self,newnode):
	Newnode=node(newnode);
	Newnode.next=self.head;
	self.head=Newnode;
	if self.head is None:
	self.head.prev=Newnode;
	self.head=Newnode;
	def insertdata(self,newnode):
	Newnode=node(newnode);
	Newnode.next=self.head;
	self.head=Newnode;
	if self.head is None:
	self.head.next.prev=Newnode;
	self.head=Newnode;
	def insertmiddle(self,mid,newnode):
	Newnode=node(newnode);
	Newnode.next=mid.next;
	mid.next=Newnode;
	Newnode.prev=mid.next;
	if Newnode.prev:
	Newnode.next.prev=Newnode;
	def insertlast(self,newnode):
	Newnode=node(newnode);
	Newnode.next=None;
	if self.head is None:
	Newnode.prev=None;
	self.head=Newnode;
	return;
	last=self.head;
	while last.next is not None:
	last=last.next;
	last.next=Newnode;
	Newnode.prev=last;
	def deletenode(self,remove):
	Head=self.head;
	if Head is not None:
	if Head.data==remove:
	self.head=Head.next;
	Head=None;
	return;
	while Head is not None:
	if Head.data==remove:
	break;
	last=Head;
	Head=Head.next;
	if Head==None:
	return;
	last.next=Head.next;
	Head=None;
	def display(self):
	show=self.head;
	while show:
	print(show.data);
	last=show;
	show=show.next;
	obj=DoublyLinked();
	obj.adddata(int(input('enter the item =')));
	obj.adddata(int(input('enter the item=')));
	obj.adddata(int(input('enter the item=')));
	obj.adddata(int(input('enter the item=')));
	obj.adddata(int(input('enter the item=')));
	obj.adddata(int(input('enter the item=')));
	obj.display();
	obj.insertdata(int(input('enter the item=')));
	obj.display();
	obj.insertmiddle(obj.head.next,int(input('enter the number==>')));
	obj.display();
	obj.insertlast(int(input('enter the number==>>')));
	obj.display();
	obj.deletenode(int(input('enter the number for delete==>>>>>')));
	obj.display();

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insert:

	def insertdata(self,newnode):
	Newnode=node(newnode);
	Newnode.next=self.head;
	self.head=Newnode;
	if self.head is None:
	self.head.next.prev=Newnode;
	self.head=Newnode;

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Add node Middle:

	def insertmiddle(self,mid,newnode):
	Newnode=node(newnode);
	Newnode.next=mid.next;
	mid.next=Newnode;
	Newnode.prev=mid.next;
	if Newnode.prev:
	Newnode.next.prev=Newnode;

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Add node last

	def insertlast(self,newnode):
	Newnode=node(newnode);
	Newnode.next=None;
	if self.head is None:
	Newnode.prev=None;
	self.head=Newnode;
	return;
	last=self.head;
	while last.next is not None:
	last=last.next;
	last.next=Newnode;
	Newnode.prev=last;

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Delete Node

	def deletenode(self,remove):
	Head=self.head;
	if Head is not None:
	if Head.data==remove:
	self.head=Head.next;
	Head=None;
	return;
	while Head is not None:
	if Head.data==remove:
	break;
	last=Head;
	Head=Head.next;
	if Head==None:
	return;
	last.next=Head.next;
	Head=None;

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